body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
}

.container {
    position: relative;
    width: 640px;
    height: 480px;
    border: 5px solid #333;
    border-radius: 10px;
    overflow: hidden;
}

.input_video, .output_canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    transform: scaleX(-1);
}

.output_canvas {
    z-index: 10;
}

#clear-btn {
    margin-bottom: 15px;
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    background-color: #f44336;
    color: white;
    border: none;
    border-radius: 5px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
    transition: background-color 0.3s;
}

#clear-btn:hover {
    background-color: #d32f2f;
}

#countdown-display {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 200px;
    font-weight: bold;
    color: rgba(255, 255, 255, 0.7);
    text-shadow: 0 0 15px rgba(0, 0, 0, 0.5);
    z-index: 20;
    pointer-events: none;
    font-family: 'Courier New', Courier, monospace;
    visibility: hidden;
}
